The present invention relates to a cleaning device for cleaning a photosensitive member, a transfer portion, or the like, in a dry electrophotographic device.
FIG. 6 shows a cleaning device in a conventional dry electrophotographic device in which toner 2, remaining on the surface of a photosensitive drum 1 after the respective processes of charging, exposure, development and transfer have been performed, is mechanically removed by a cleaning brush 3, or electrostatically removed when a brush bias-voltage applying mechanism 7 is employed. The toner 2 magnetically or electrostatically adhering to the cleaning roll 4 is scraped off mechanically by a cleaning blade 5 and is discharged from the device by a toner recovery screw 6.
Cleaning brush 3 has fine metallic bristles or the like, and cleaning roll 4 is brought into contact with cleaning brush 3 with a prescribed pressure so that toner 2 adhering to cleaning brush 3 can be transferred reliably to the cleaning roll 4.
Since the cleaning brush 3 and the cleaning roll 4 of the conventional cleaning device constantly and resiliently contact each other, the fine metallic bristles of the cleaning brush 3 are flattened over time. Therefore, the outer diameter of the cleaning brush 3 decreases gradually, so that the conventional cleaning device has a short service life in that the contact area between the cleaning brush 3 and the photosensitive drum gradually decreases, thereby deteriorating the cleaning capability of the cleaning device.